1. Field of the Invention
The present invention relates generally to implantable prostheses and in particular to a securing member configured to lock into an implant.
2. Description of Related Art
Locking screws configured to implant into bone have been previously proposed. Reynolds (U.S. publication number 2007/0073297) teaches an implant with integral fastener retention. Reynolds teaches an implant to provide a simple yet effective retention system requiring no additional components beyond the implant and the associated fastener. Reynolds teaches a plurality of anti-rotation protrusions that are provided on fasteners that match recesses in an implant. As the fasteners engage the surface of the implant, protrusions engage the recesses and anti-backout surface of the recesses prevent the fastener from backing out.
The anti-rotation protrusions taught by Reynolds may engage side walls of the implant hole prior to engaging the recesses. This may lead to difficulty with inserting the screw correctly or efficiently. Furthermore, the location of the recesses makes it difficult to view the engagement of the anti-rotation protrusions with the recesses during implantation. This means that a surgeon may not know exactly when the engagement has occurred unless the surgeon attempts to rotate the screw in reverse.
Talaber (U.S. Pat. No. 6,261,291) teaches an orthopedic implant assembly. In the Talaber design, a securing element has a plurality of circumferentially spaced members. The spaced members initially deflect to fit through a collar of a transverse passageway and then expand to an uncompressed configuration by release of the radially compressive force of the collar.
Talaber teaches a securing element that is compressed and then uncompressed during implantation. This process of compressing and successively uncompressing could weaken the connection between the circumferentially spaced members and the base of the securing element.
There is a need in the art for a design that overcomes these shortcomings of the prior art.